Ternary metal oxide catalysts for selective oxidation of benzene to phenol

This paper studied the liquid phase hydroxylation of benzene to phenol with hydrogen peroxide catalyzed by ternary metal oxide catalysts (Fe(III), V(V) and Cu(II)) supported on TiO2 at room temperature. The effects of V(V) and Cu(II) metal oxide loading were investigated. The catalysts were prepared by co-impregnation method and characterized by BET, XRD, XRF, SEM-EDX, NH3-TPD techniques. It was reported that the presence of V(V) and Cu(II) influenced the acid property on the catalyst. The increase of the metal loading increased the acidity of the catalyst. TiO2 loaded with Fe, V and Cu of 5, 2.5 and 2.5 wt%, respectively offered the highest yield of phenol. Although the increase of the metal loading improved the yield of phenol, the TOF reduced due to the reduction of dispersion of the catalyst metal. The optimum condition for the system is a reaction time of 4 h, catalyst weight of 0.2 g, the H2O2:benzene molar ratio of 2 and 6.25 g of ascorbic acid per mole of benzene.